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Carine Karachi - One of the best experts on this subject based on the ideXlab platform.
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The anatomo-functional organization of the hyperdirect Cortical Pathway to the subthalamic area using in vivo structural connectivity imaging in humans
Brain Structure and Function, 2020Co-Authors: Gizem Temiz, Sophie B. Sébille, Chantal Francois, Eric Bardinet, Carine KarachiAbstract:The subthalamic nucleus (STN) receives direct Cortical inputs which constitute the so-called hyperdirect Pathway. In monkeys, motor cortices innervate the whole extent of the STN whereas limbic cortices innervate only its anteromedial part extending more medially outside the nucleus. Tractography studies in humans have also identified motor Cortical inputs to the STN, but little is known about the associative and limbic Cortical projections. Therefore, the aim of this study was to investigate the anatomo-functional organization of the Cortical projections to the STN and to the adjacent medial subthamic region (MSR). We used diffusion-weighted imaging-based tractography acquired from 30 subjects from the Human Connectome Project. We performed a whole-brain probabilistic tractography using MRTrix and extracted streamlines of interest between 39 Cortical masks and both the STN and the MSR to provide track-density maps. Agglomerative clustering method was used to classify the voxels of the regions of interest. We found that the STN receives major inputs from the sensorimotor cortices and few inputs from the limbic cortices. On the other hand, the MSR receives mainly Cortical limbic projections and few from the sensorimotor cortices. Weak connections were found between the associative cortices and both the STN and the MSR. We found a dominant motor cluster located in the posterolateral STN, a limbic cluster located medially in the MSR, and an intermediate motor-limbic cluster in between. Our findings show that the hyperdirect Pathway is anatomo-functionally organized with a poor participation of associative cortices.
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The anatomo‐functional organization of the hyperdirect Cortical Pathway to the subthalamic area using in vivo structural connectivity imaging in humans
Brain Structure and Function, 2019Co-Authors: Gizem Temiz, Sophie B. Sébille, Chantal Francois, Eric Bardinet, Carine KarachiAbstract:The subthalamic nucleus (STN) receives direct Cortical inputs which constitute the so-called hyperdirect Pathway. In monkeys, motor cortices innervate the whole extent of the STN whereas limbic cortices innervate only its anteromedial part extending more medially outside the nucleus. Tractography studies in humans have also identified motor Cortical inputs to the STN, but little is known about the associative and limbic Cortical projections. Therefore, the aim of this study was to investigate the anatomo-functional organization of the Cortical projections to the STN and to the adjacent medial subthamic region (MSR). We used diffusion-weighted imaging-based tractography acquired from 30 subjects from the Human Connectome Project. We performed a whole-brain probabilistic tractography using MRTrix and extracted streamlines of interest between 39 Cortical masks and both the STN and the MSR to provide track-density maps. Agglomerative clustering method was used to classify the voxels of the regions of interest. We found that the STN receives major inputs from the sensorimotor cortices and few inputs from the limbic cortices. On the other hand, the MSR receives mainly Cortical limbic projections and few from the sensorimotor cortices. Weak connections were found between the associative cortices and both the STN and the MSR. We found a dominant motor cluster located in the posterolateral STN, a limbic cluster located medially in the MSR, and an intermediate motor-limbic cluster in between. Our findings show that the hyperdirect Pathway is anatomo-functionally organized with a poor participation of associative cortices.
L. Rispal-padel - One of the best experts on this subject based on the ideXlab platform.
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Functional plasticity in the interposito-thalamo-Cortical Pathway during conditioning. Role of the interstimulus interval.
Experimental Brain Research, 2000Co-Authors: Marc Pananceau, L. Rispal-padelAbstract:In classic conditioning, the interstimulus interval (ISI) between the conditioned (CS) and unconditioned (US) stimulus is a critical parameter. The aim of the present experiment was to assess whether, during conditioning, modification of the CS-US interval could reliably produce changes in the functional properties of the interposito-thalamo-Cortical Pathways (INTCps). Five cats were prepared for chronic stimulation and recording from several brain regions along this Pathway in awake animals. The CS was a weak electric shock applied on the interposed nucleus of the cerebellum in sites that initially elicited forelimb flexion (i.e., alpha motor responses) in three cats, and equal proportions of flexor and extensor responses in two cats. The US was an electric shock applied on the skin that elicited forelimb flexions. The motor and neurobiological effects of synchronous CS-US were compared with pairings in which the CS was applied 100 ms before US. Simultaneous and sequential application of CS and US produced different behavioral outcomes and resulted in different neural processes in the interposito-thalamo-Cortical Pathways (INTCps). The simultaneous presentation of stimuli only produced a small increase in excitability spreading to all the body representational zones of the primary motor cortex and a weak increase in the amplitude of the alpha motor response. In contrast, the sequential application led to a profound modification of the interposed output to neurons in the forelimb representation of the motor cortex. These robust neuronal correlates of conditioning were accompanied by a large facilitation of the alpha motor response (alpha-MR). There were also changes in the direction of misdirected alpha responses and an emergence of functionally appropriate, long-latency withdrawal forelimb flexion. These data revealed that, during conditioning, plastic changes within the thalamoCortical connections are selectively induced by sequential information from central and peripheral afferents. This sequence significantly contributed to neural processes that are responsible for the acquisition, expression, and extinction of anticipatory flexion responses.
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Functional plasticity in the interposito-thalamo-Cortical Pathway during conditioning
Experimental brain research, 2000Co-Authors: Marc Pananceau, L. Rispal-padelAbstract:In classic conditioning, the interstimulus interval (ISI) between the conditioned (CS) and unconditioned (US) stimulus is a critical parameter. The aim of the present experiment was to assess whether, during conditioning, modification of the CS-US interval could reliably produce changes in the functional properties of the interposito-thalamo-Cortical Pathways (INTCps). Five cats were prepared for chronic stimulation and recording from several brain regions along this Pathway in awake animals. The CS was a weak electric shock applied on the interposed nucleus of the cerebellum in sites that initially elicited forelimb flexion (i.e., alpha motor responses) in three cats, and equal proportions of flexor and extensor responses in two cats. The US was an electric shock applied on the skin that elicited forelimb flexions. The motor and neurobiological effects of synchronous CS-US were compared with pairings in which the CS was applied 100 ms before US. Simultaneous and sequential application of CS and US produced different behavioral outcomes and resulted in different neural processes in the interposito-thalamo-Cortical Pathways (INTCps). The simultaneous presentation of stimuli only produced a small increase in excitability spreading to all the body representational zones of the primary motor cortex and a weak increase in the amplitude of the alpha motor response. In contrast, the sequential application led to a profound modification of the interposed output to neurons in the forelimb representation of the motor cortex. These robust neuronal correlates of conditioning were accompanied by a large facilitation of the alpha motor response (α-MR). There were also changes in the direction of misdirected alpha responses and an emergence of functionally appropriate, long-latency withdrawal forelimb flexion. These data revealed that, during conditioning, plastic changes within the thalamoCortical connections are selectively induced by sequential information from central and peripheral afferents. This sequence significantly contributed to neural processes that are responsible for the acquisition, expression, and extinction of anticipatory flexion responses.
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Synaptic plasticity in the thalamo-Cortical Pathway as one of the neurobiological correlates of forelimb flexion conditioning: electrophysiological investigation in the cat.
Journal of neurophysiology, 1994Co-Authors: El Mehdi Meftah, L. Rispal-padelAbstract:1. In a previous study, using a chronic cat preparation subjected to an associative conditioning procedure, we described the plasticity of the thalamo-Cortical Pathway by qualitatively and quantita...
Ron Kupers - One of the best experts on this subject based on the ideXlab platform.
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A thalamoCortical Pathway for fast rerouting of tactile information to occipital cortex in congenital blindness
Nature communications, 2019Co-Authors: Franziska Müller, Guiomar Niso, Soheila Samiee, Maurice Ptito, Sylvain Baillet, Ron KupersAbstract:In congenitally blind individuals, the occipital cortex responds to various nonvisual inputs. Some animal studies raise the possibility that a subCortical Pathway allows fast re-routing of tactile information to the occipital cortex, but this has not been shown in humans. Here we show using magnetoencephalography (MEG) that tactile stimulation produces occipital cortex activations, starting as early as 35 ms in congenitally blind individuals, but not in blindfolded sighted controls. Given our measured thalamic response latencies of 20 ms and a mean estimated lateral geniculate nucleus to primary visual cortex transfer time of 15 ms, we claim that this early occipital response is mediated by a direct thalamo-Cortical Pathway. We also observed stronger directed connectivity in the alpha band range from posterior thalamus to occipital cortex in congenitally blind participants. Our results strongly suggest the contribution of a fast thalamo-Cortical Pathway in the cross-modal activation of the occipital cortex in congenitally blind humans. In congenitally blind people, tactile stimuli can activate the occipital (visual) cortex. Here, the authors show using magnetoencephalography (MEG) that occipital activation can occur within 35 ms following tactile stimulation, suggesting the existence of a fast thalamoCortical Pathway for touch in congenitally blind humans.
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TMS of the occipital cortex induces tactile sensations in the fingers of blind Braille readers
Experimental brain research, 2007Co-Authors: Maurice Ptito, Arnaud Fumal, A. Martens De Noordhout, Jean Schoenen, Albert Gjedde, Ron KupersAbstract:Various non-visual inputs produce cross-modal responses in the visual cortex of early blind subjects. In order to determine the qualitative experience associated with these occipital activations, we systematically stimulated the entire occipital cortex using single pulse transcranial magnetic stimulation (TMS) in early blind subjects and in blindfolded seeing controls. Whereas blindfolded seeing controls reported only phosphenes following occipital cortex stimulation, some of the blind subjects reported tactile sensations in the fingers that were somatotopically organized onto the visual cortex. The number of Cortical sites inducing tactile sensations appeared to be related to the number of hours of Braille reading per day, Braille reading speed and dexterity. These data, taken in conjunction with previous anatomical, behavioural and functional imaging results, suggest the presence of a polysynaptic Cortical Pathway between the somatosensory cortex and the visual cortex in early blind subjects. These results also add new evidence that the activity of the occipital lobe in the blind takes its qualitative expression from the character of its new input source, therefore supporting the Cortical deference hypothesis.
Gizem Temiz - One of the best experts on this subject based on the ideXlab platform.
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The anatomo-functional organization of the hyperdirect Cortical Pathway to the subthalamic area using in vivo structural connectivity imaging in humans
Brain Structure and Function, 2020Co-Authors: Gizem Temiz, Sophie B. Sébille, Chantal Francois, Eric Bardinet, Carine KarachiAbstract:The subthalamic nucleus (STN) receives direct Cortical inputs which constitute the so-called hyperdirect Pathway. In monkeys, motor cortices innervate the whole extent of the STN whereas limbic cortices innervate only its anteromedial part extending more medially outside the nucleus. Tractography studies in humans have also identified motor Cortical inputs to the STN, but little is known about the associative and limbic Cortical projections. Therefore, the aim of this study was to investigate the anatomo-functional organization of the Cortical projections to the STN and to the adjacent medial subthamic region (MSR). We used diffusion-weighted imaging-based tractography acquired from 30 subjects from the Human Connectome Project. We performed a whole-brain probabilistic tractography using MRTrix and extracted streamlines of interest between 39 Cortical masks and both the STN and the MSR to provide track-density maps. Agglomerative clustering method was used to classify the voxels of the regions of interest. We found that the STN receives major inputs from the sensorimotor cortices and few inputs from the limbic cortices. On the other hand, the MSR receives mainly Cortical limbic projections and few from the sensorimotor cortices. Weak connections were found between the associative cortices and both the STN and the MSR. We found a dominant motor cluster located in the posterolateral STN, a limbic cluster located medially in the MSR, and an intermediate motor-limbic cluster in between. Our findings show that the hyperdirect Pathway is anatomo-functionally organized with a poor participation of associative cortices.
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The anatomo‐functional organization of the hyperdirect Cortical Pathway to the subthalamic area using in vivo structural connectivity imaging in humans
Brain Structure and Function, 2019Co-Authors: Gizem Temiz, Sophie B. Sébille, Chantal Francois, Eric Bardinet, Carine KarachiAbstract:The subthalamic nucleus (STN) receives direct Cortical inputs which constitute the so-called hyperdirect Pathway. In monkeys, motor cortices innervate the whole extent of the STN whereas limbic cortices innervate only its anteromedial part extending more medially outside the nucleus. Tractography studies in humans have also identified motor Cortical inputs to the STN, but little is known about the associative and limbic Cortical projections. Therefore, the aim of this study was to investigate the anatomo-functional organization of the Cortical projections to the STN and to the adjacent medial subthamic region (MSR). We used diffusion-weighted imaging-based tractography acquired from 30 subjects from the Human Connectome Project. We performed a whole-brain probabilistic tractography using MRTrix and extracted streamlines of interest between 39 Cortical masks and both the STN and the MSR to provide track-density maps. Agglomerative clustering method was used to classify the voxels of the regions of interest. We found that the STN receives major inputs from the sensorimotor cortices and few inputs from the limbic cortices. On the other hand, the MSR receives mainly Cortical limbic projections and few from the sensorimotor cortices. Weak connections were found between the associative cortices and both the STN and the MSR. We found a dominant motor cluster located in the posterolateral STN, a limbic cluster located medially in the MSR, and an intermediate motor-limbic cluster in between. Our findings show that the hyperdirect Pathway is anatomo-functionally organized with a poor participation of associative cortices.
Eric Bardinet - One of the best experts on this subject based on the ideXlab platform.
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The anatomo-functional organization of the hyperdirect Cortical Pathway to the subthalamic area using in vivo structural connectivity imaging in humans
Brain Structure and Function, 2020Co-Authors: Gizem Temiz, Sophie B. Sébille, Chantal Francois, Eric Bardinet, Carine KarachiAbstract:The subthalamic nucleus (STN) receives direct Cortical inputs which constitute the so-called hyperdirect Pathway. In monkeys, motor cortices innervate the whole extent of the STN whereas limbic cortices innervate only its anteromedial part extending more medially outside the nucleus. Tractography studies in humans have also identified motor Cortical inputs to the STN, but little is known about the associative and limbic Cortical projections. Therefore, the aim of this study was to investigate the anatomo-functional organization of the Cortical projections to the STN and to the adjacent medial subthamic region (MSR). We used diffusion-weighted imaging-based tractography acquired from 30 subjects from the Human Connectome Project. We performed a whole-brain probabilistic tractography using MRTrix and extracted streamlines of interest between 39 Cortical masks and both the STN and the MSR to provide track-density maps. Agglomerative clustering method was used to classify the voxels of the regions of interest. We found that the STN receives major inputs from the sensorimotor cortices and few inputs from the limbic cortices. On the other hand, the MSR receives mainly Cortical limbic projections and few from the sensorimotor cortices. Weak connections were found between the associative cortices and both the STN and the MSR. We found a dominant motor cluster located in the posterolateral STN, a limbic cluster located medially in the MSR, and an intermediate motor-limbic cluster in between. Our findings show that the hyperdirect Pathway is anatomo-functionally organized with a poor participation of associative cortices.
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The anatomo‐functional organization of the hyperdirect Cortical Pathway to the subthalamic area using in vivo structural connectivity imaging in humans
Brain Structure and Function, 2019Co-Authors: Gizem Temiz, Sophie B. Sébille, Chantal Francois, Eric Bardinet, Carine KarachiAbstract:The subthalamic nucleus (STN) receives direct Cortical inputs which constitute the so-called hyperdirect Pathway. In monkeys, motor cortices innervate the whole extent of the STN whereas limbic cortices innervate only its anteromedial part extending more medially outside the nucleus. Tractography studies in humans have also identified motor Cortical inputs to the STN, but little is known about the associative and limbic Cortical projections. Therefore, the aim of this study was to investigate the anatomo-functional organization of the Cortical projections to the STN and to the adjacent medial subthamic region (MSR). We used diffusion-weighted imaging-based tractography acquired from 30 subjects from the Human Connectome Project. We performed a whole-brain probabilistic tractography using MRTrix and extracted streamlines of interest between 39 Cortical masks and both the STN and the MSR to provide track-density maps. Agglomerative clustering method was used to classify the voxels of the regions of interest. We found that the STN receives major inputs from the sensorimotor cortices and few inputs from the limbic cortices. On the other hand, the MSR receives mainly Cortical limbic projections and few from the sensorimotor cortices. Weak connections were found between the associative cortices and both the STN and the MSR. We found a dominant motor cluster located in the posterolateral STN, a limbic cluster located medially in the MSR, and an intermediate motor-limbic cluster in between. Our findings show that the hyperdirect Pathway is anatomo-functionally organized with a poor participation of associative cortices.
